[vsnet-grb-info 10137] GRB 110119A: Swift-XRT refined Analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11586
SUBJECT: GRB 110119A: Swift-XRT refined Analysis
DATE:    11/01/20 14:46:32 GMT
FROM:    Valerio D'Elia at ASDC  <delia at asdc.asi.it>

V. D'Elia, G. Stratta (ASDC), E. Troja (NASA/GSFC/ORAU) report on
behalf of the Swift-XRT team:

We have analysed 18 ks of XRT data for GRB 110119A (Troja  et al. GCN
Circ. 11581), from 48 s to 45.5 ks after the  BAT trigger. The data
comprise 358 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN. Circ 11582).

The late-time light curve (from T0+4.9 ks) can be modelled with  a
power-law decay with a decay index of alpha=1.64 (+/-0.10).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 1.56 (+/-0.03). The
best-fitting absorption column is  1.80 (+/-0.11) x 10^21 cm^-2, in
excess of the Galactic value of 6.4 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.23 (+0.12, -0.11)
and a best-fitting absorption column of 1.29 (+0.26, -0.14) x 10^21
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.5 x 10^-11 (5.2 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.29 (+0.26, -0.14) x 10^21 cm^-2
Galactic foreground: 6.4 x 10^20 cm^-2
Excess significance: 15.3 sigma
Photon index:	     2.23 (+0.12, -0.11)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00442978.

This circular is an official product of the Swift-XRT team.